/* The following code example is taken from the book
 * "The C++ Standard Library - A Tutorial and Reference, 2nd Edition"
 * by Nicolai M. Josuttis, Addison-Wesley, 2012
 *
 * (C) Copyright Nicolai M. Josuttis 2012.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <iostream>
#include <valarray>

using namespace std;

// print valarray line-by-line
template<typename T>
void printValarray(const valarray <T> &va, int num) {
    for (int i = 0; i < va.size() / num; ++i) {
        for (int j = 0; j < num; ++j) {
            cout << va[i * num + j] << ' ';
        }
        cout << endl;
    }
    cout << endl;
}

int main() {
    // valarray with 12 elements
    // - four rows
    // - three columns
    valarray<double> va(12);

    // fill valarray with values
    for (int i = 0; i < 12; i++) {
        va[i] = i;
    }

    printValarray(va, 3);

    // assign 77 to all values that are less than 5
    va[va < 5.0] = 77.0;

    // add 100 to all values that are greater than 5 and less than 9
    va[va > 5.0 && va < 9.0]
            = valarray<double>(va[va > 5.0 && va < 9.0]) + 100.0;

    printValarray(va, 3);
}
